CREDO Study: Charter School Performance Improving, But Gaps Remain

A new study finds that charter school performance is improving nationwide, although gaps remain in performance between the worst charters and the best. The study was conducted by the Center for Research on Education Outcomes (CREDO) at Stanford University and serves as an update to a widely-cited 2009 CREDO study that was one of the first to take a comprehensive look at how charters stack up against traditional public schools.

The 2009 edition was largely a dose of bad news for charter advocates. Then, no significant differences in student performance were found between public school students and those enrolled in charter schools.

But this time around, the news is much better. Researchers write that, on average, students enrolled in charter schools receive an equivalent of 8 additional days of instruction in reading compared to their public school counterparts.

In mathematics, the 2013 study found no significant difference in learning, whereas the 2009 study found that charter school students had the equivalent of 22 fewer days of learning. The gains for poor and minority students and English language learners were even greater.

“The general reaction to the 2009 study was shock and disbelief,” says Margaret Raymond, the director of CREDO. “It was the first time we as researchers could provide enough of a wide-angle view for people to understand they’d gotten their doctors’ report back and the news wasn’t all that great.

CREDO used a ‘virtual twin’ approach to analyze student performance instead of comparing charters and public schools directly to each other. To compare outcomes, researchers formed composites of public school students who fit the profile of a charter student who would have otherwise attended that public school.

While the performance of charters has improved substantially since the 2009 study – especially for the most academically disadvantaged students – variance in quality remains great state to state and between schools.

In this study, 19 percent of charter schools posted gains in reading that were significantly weaker than their traditional public counterparts, and 31 percent were weaker in math. Greg Richmond, president and CEO of the National Association of Charter School Authorizers, notes that these are similar to his organization’s finding last fall that between 900 and 1300 charter schools were performing in the bottom 15 percent of their state’s accountability system.